Host Defense Response and Outcome in ARDS

Abstract

The host defense response (HDR) to an insult consists of an interactive network of simultaneously activated pathways—inflammation, coagulation (intravascular clotting and extravascular fibrin deposition), tissue repair, modulation of the immune response, and activation of the hypothalamic-pituitary-adrenal (HPA) axis with production of glucocorticoids—that act in synergy to increase the host's chance of survival. 1 Meduri G.U. The role of the host defense response in the progression and outcome of ARDS: pathophysiological correlations and response to glucocorticoid treatment. Eur Respir J. 1996; 9: 2650-2670 Crossref PubMed Scopus (109) Google Scholar Sympathetic system release of catecholamines and hepatic production of acute-phase reactants are an integral part of the HDR and are under the influence of glucocorticoids. Tissue repair consists of angiogenesis, epithelial growth, fibroblast migration and proliferation (fibroproliferation), and deposition of the extracellular matrix. In this issue of CHEST (see page 1184), Deheinzelin and collaborators provide additional evidence that tissue repair starts soon after exposure to an insult, a finding in agreement with prior clinical 2 Clark J.G. Milberg J.A. Steinberg K.P. et al. Type III procollagen peptide in the adult respiratory distress syndrome: association of increased peptide levels in bronchoalveolar lavage fluid with increased risk for death. Ann Intern Med. 1995; 122: 17-23 Crossref PubMed Scopus (192) Google Scholar , 3 Chesnut A.N. Matthay M.A. Clark J.G. Type III procollagen peptide is present in pulmonary edema fluid on day one in patients with acute respiratory distress syndrome (ARDS) [abstract]. Am J Respir Crit Care Med. 1996; 153 (All.) Google Scholar and experimental 4 Mikulaschek A. Trooskin S.Z. Winfield J. et al. Pulmonary fibroblast function in an acute lung injury model. J Trauma. 1995; 39: 59-66 Crossref PubMed Scopus (3) Google Scholar work in early acute respiratory distress syndrome (ARDS).